Cincinnati Milacron Inc.

John S Hsu

Lynn M Tore

An accumulator head is convertible to alternate capacity ranges by providing a construction that has a segmented barrel with a matching ram in the purging system. More specifically, the accumulator barrel is divided into upper and lower segments so that the accumulator chamber is bounded by the lower barrel segment. The inner diameter of the lower barrel segment matches the outer diameter of the ram, and the length of the lower barrel segment corresponds roughly to the range of movement of the ram. With this accumulator construction, it is possible to change the working volume of the internal accumulator chamber by simply changing two parts, i.e., the lower barrel segment (inner diameter) and the ram (outer diameter). In addition, the two piece accumulator barrel design facilitates a more economical construction since the lower segment (where most of the wear occurs) can be made of a wear resistant grade of steel, while the upper segment can be manufactured from a lower cost, more easily machined material.

Accumulator head having a segmented barrel

The accumulator of an extrusion blow molding machine is constructed so that the programming cylinder and die adjustment rod have axially aligned bores to receive a die pin retaining rod. The retaining rod holds the die pin in place by means of a lower split ring that nests inside the die pin and a lock nut combined with an upper split ring associated with the programming cylinder. When the lock nut is loosened and the upper split ring is removed, the retaining rod is moved down (while the die pin is held in place) and the lower split ring is removed. The die pin is then free to slide off the retaining rod and be removed from the accumulator head.

Retainer for the die pin in an accumulator head

An extruder screw mixing head that is adapted to be carried by an extruder screw at a downstream portion of the screw for improved distributive mixing. The mixing head includes a central body that tapers and diverges in a downstream direction to provide a progressively diminishing flow channel in an axial direction of the mixing head. Four equally spaced flights of equal pitch are provided on the outer periphery of the mixing head, and each flight has a series of peripheral recesses that are spaced from each other along the flights and that permit flow of plasticated material between adjacent flow channels defined by the spaced flights to improve homogeneity of the material. The recesses are so configured that their respective leading and trailing edges are aligned to define circumferential angles with the longitudinal axis of the mixing head, so that the inter-channel flow areas of the recesses increase in a direction toward the outlet of the extruder barrel. The taper of the center portion of the mixing head causes a reduction in the flow areas of the channels in a downstream direction, which encourages inter-channel flow to thereby promote improved mixing of the material being conveyed by the extruder screw.

Extruder screw mixing head

An accumulator head for an extrusion-blow molding machine. The accumulator head includes an annular inner sleeve member slidably positioned within an accumulator outer barrel, and a tubular inner body member received within the sleeve member. The sleeve member and body member are adapted to be slidable together within the accumulator barrel to expel collected plasticated material. The inner sleeve member includes a pair of external slots formed in the outer surface that communicate with the accumulator inlet and with respective radially extending flow passageways through the inner sleeve to convey plasticated material from the accumulator inlet into a pair of helical flow channels formed in the accumulator inner body member. The flow channels communicate with an outlet area to convey the plasticated material to an inner accumulation chamber through an annular collector channel and an annular flow passageway that provides an extruded parison having a uniform conformation without flow or separation lines. Suitable actuators are provided for together moving the inner sleeve and the inner body member to expel plasticated material, and also to selectively move an inner mandrel to provide a desired parison die outlet opening.

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Cincinnati, OH, United States of America

John S Hsu